Determinants of survival in captive-bred Griffon Vultures Gyps fulvus after their release to the wild

Conservation translocations are a wide-spread tool commonly used to prevent the extinction of species locally and globally. However, conservation translocations are complicated operations which often fail, especially when they involve the release of captive-bred animals. In order to survive, translocated animals need to adapt to a new environment; the success of this adaptation depends, to a large extent, on the characteristics of the release environment and on early life experiences that can affect the animals' proficiencies. We tested the effects of different early life experiences and differences in the release environment on the survival of captive-bred translocated Griffon Vultures (Gyps fulvus) in Israel, where they are critically endangered. We used a mark-resight approach to calculate survival using a large dataset containing 9 years of observations of individually-marked vultures. We found that the Griffon Vultures' survival was positively affected by their age at release and the time they spent in the wild. We also found that survival was affected by rearing method, release site and release season. Our results emphasize the critical importance of the release protocol to the success of a conservation translocation project. Furthermore, our results show how events occurring during the entire pre-release period can have important repercussions many years later when the captive animal is released into the wild, but also that experience gained post-release plays a major role in the animals' survival.